Glucose "peak" and glucose "spike": Impact on endothelial function and oxidative stress.
OBJECTIVE
Data suggest that 2h hyperglycaemia during an OGTT is less predictive for cardiovascular disease of the glucose "spike" (the difference between the baseline glucose level and the "peak" hyperglycaemia during the test).


METHODS
A euinsulinemic hyperglycaemic clamp at 10 and 15mmol/l glucose, with or without vitamin C, was given in increasing steps in diabetic and normal subjects. Moreover, a hyperglycaemic clamp, 10mmol/l, was performed in two groups of diabetic patients with different levels of fasting glycaemia. In both the experiments flow mediated dilation and nitrotyrosine were measured.


RESULTS
Glucose at 10 and 15mmol/l resulted in a concentration-dependent induction of endothelial dysfunction and oxidative stress. Vitamin C counterbalanced this effect. The increase of glycaemia to 10mmol/l induced a significant endothelial dysfunction and increased nitrotyrosine in both the groups of diabetics with different fasting glycaemia. However, when the delta (the difference between the basal value and the peak value) for endothelial function and nitrotyrosine was evaluated, patients with lower basal values showed a worse outcome.


CONCLUSIONS
Our data suggest that at the same level of hyperglycaemia the grading of the endothelial dysfunction is almost super imposable, but clearly worse in terms of delta from fasting glycaemia.
Ceriello
Antonio
A
Centre of Excellence in Diabetes and Endocrinology, University Hospital of Coventry and Warwickshire, Warwick Medical School, University of Warwick, Coventry, UK. antonio.ceriello@warwick.ac.uk
Esposito
Katherine
K
Piconi
Ludovica
L
Ihnat
Michael
M
Thorpe
Jessica
J
Testa
Roberto
R
Bonfigli
Anna Rita
AR
Giugliano
Dario
D
D004730:Endothelium, Vascular / Q000187:drug effects*; D005260:Female; D005947:Glucose / Q000494:pharmacology*; D015309:Glucose Clamp Technique; D005951:Glucose Tolerance Test; D006801:Humans; D006943:Hyperglycemia / Q000139:chemically induced; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress / Q000187:drug effects*
D005947:Glucose